Bicycles have undergone significant design developments and a number of specialized classifications have evolved (e.g., racing, touring, mountain). These classifications typically utilize, for instance, different frame geometries, constructions, and gear ratios, and some even necessitate or accommodate for different rider orientations to optimize performance under a particular set of conditions. Notwithstanding the many variations between the classifications and in fact within the classifications themselves, the saddle remains a primary structure in the interaction between the rider and the bicycle.
The interaction between the rider and the saddle has a significant effect on the comfort accorded the rider and the performance which the rider is able to achieve from the bicycle. When taking rider comfort into consideration in saddle design, the weight of the rider acting upon the saddle should generally be distributed over as large an area as possible to reduce concentrated pressure (i.e., the application of the same magnitude of force over a larger area reduces pressure) In a static analysis, the optimum saddle width would thus be equal to that of the rider's buttocks such that the rider's two ischial tuberosities would each effectively sustain one-half of the rider's weight. However, dynamically this saddle width could adversely affect not only rider comfort, but the level of performance that a rider is able to achieve as well.
An efficient power stroke in pedalling a bicycle requires a substantial downward extension of the legs in an alternating fashion. The amount of this extension is controlled by the distance between the saddle and the lowest pedal position. In the event that a wide conventional saddle is vertically positioned to allow for the desired alternating leg extensions, such extensions will cause the associated ischial tuberosity and/or other adjacently located, protruding bony structures (hereinafter collectively referred to as "ischial tuberosities") to also attempt to move in a downward direction. However, the saddle resists this motion which thereby creates a localized pressure concentration which adversely affects rider comfort.
While pedalling, the ischial tuberosity associated with the leg moving toward the uppermost pedal position tends to move vertically upward and may lose contact with the conventional saddle. In this case, the ischial tuberosity of the downwardly extended leg will effectively support the entire weight of the rider. Consequently, the magnitude of the above-described localized pressure concentration is further increased. In addition to this now magnified level of rider discomfort, performance is also adversely affected in that the saddle inhibits the downward movement of the ischial tuberosity as it attempts to follow the downward extension of the leg in the power stroke.
In order to reduce the effects of the interaction of the ischial tuberosities and the conventional saddle in the above-described manner, the saddle may be positioned such that the desired leg extension is not achieved, i.e., too low. As a result, the amount of downward vertical movement of the ischial tuberosities is reduced which thereby reduces the magnitude of the associated localized pressure concentration. This gain in rider comfort, however, is accompanied by a decrease in the power that the rider is able to generate since the leg can no longer be extended to the desired degree. Moreover, as the amount of leg extension is reduced, undesirable strains and/or stresses may be introduced to the knee joints.
Based on the foregoing problems with the wide conventional saddle, narrower saddles which allow for either free vertical reciprocation of the ischial tuberosities or which allow the ischial tuberosities to contact a downwardly extending, convexly arcuate surface are commonly used by riders. Although this produces a higher performance saddle, the cost in terms of added rider discomfort is significant. Further contributing to these factors is that saddles are typically designed to fit narrow anatomical structures. As a result, larger persons using such saddles often experience an even greater magnitude of discomfort.
Many attempts have been made to design a saddle which provides a more desirable blend of rider comfort and saddle performance. One alternative is to utilize a saddle having a laterally arcuate, convexly-shaped mid portion which is wide enough such that the rider's ischial tuberosities are supported by the saddle, thereby increasing the area over which the rider's weight is applied. Again, in a static analysis this sharing of the load reduces pressure. In order to reduce the effects of the downward movement of the ischial tuberosities in the dynamic analysis, the areas of the saddle which the ischial tuberosities contact are either independently downwardly stretchable (e.g., by utilizing a thinner cross section in this region than is used in remaining portions of the saddle), or there are depressions in these areas of the saddle to engage the ischial tuberosities. U.S. Pat. No. 3,997,214 to Jacobs, issued Dec. 14, 1976; U.S. Pat. No. 4,098,537 to Jacobs, issued Jul. 4, 1978; and U.S. Pat. No. 4,218,090 to Hoffacker et al., issued Aug. 19, 1980, are generally representative of these efforts.
Other saddles have attempted to provide a blend of rider comfort and saddle performance by utilizing a split-seat configuration. For instance, U.S. Pat. No. 4,387,925 to Barker et al., issued Jun. 14, 1983, generally discloses two supports which are each freely (over a limited range of angular motion) and independently pivotable about an axis which is substantially perpendicular to the central, longitudinal axis of the bicycle. The supports are somewhat oblong and contoured to generally conform to the shape of the buttocks and the upper leg portion of the rider. Consequently, the supports effectively pivot to follow the planar motion defined by the legs in pedalling the bicycle.
U.S. Pat. No. 4,541,668 to Rouw, issued Sep. 17, 1985, utilizes a split seat configuration with a substantially similar rotational plane of motion to that of Barker et al. However, the split supports are interconnected such that when the forward portion of one support is deflected downwardly, the forward portion of the opposite support is forced upwardly to the same degree.
A second variation of a split seat configuration accommodates for three-dimensional motion. The individual seat supports are attached to an appropriate supporting structure such that the seat supports deflect according to the manner in which the forces are applied thereto by the rider. Representative of these types of saddles include U.S. Pat. No. 4,063,775 to Mesinger, issued Dec. 20, 1977; U.S. Pat. No. 4,369,998 to Blase, issued Jan. 25, 1983; and U.S. Pat. No. 4,512,608 to Erani, issued Apr. 23, 1985.
Notwithstanding the advancements in cycle saddle design, there remains a need for a saddle which provides for rider comfort without adversely affecting the performance that the rider is able to achieve to a significant degree.